1. Field of the Invention
The present invention relates to an ink-jet type image recording apparatus which includes a recording head having a nozzle surface in which a plurality of nozzle groups is formed, and which performs recording by jetting an ink onto a recording medium, a suction cap which covers the nozzle groups and through which the ink is sucked from the nozzle groups, and a preserving cap which covers the nozzle groups to preserve the ink when the recording head is not used. The present invention also relates to a purge mechanism which purges the recording head.
2. Description of the Related Art
An ink-jet type image recording apparatus jets an ink toward a recording medium such as a plain paper. Characters and images expressed in dots are recorded by adhering droplets of the ink jetted onto a surface of the recording medium. The droplets of ink are jetted at a high speed toward the recording medium from a nozzle group including a plurality of fine nozzles provided in a nozzle surface of a recording head. When there is a clog in the nozzle due to hardening (drying) of the ink and/or adhering of dust, or when there is an air bubble in the nozzle, it leads to defects such as a decline in an accuracy of landing of the ink droplets, and/or unevenness in an amount of ink which is jetted, and an image quality is declined.
Japanese Patent Application Laid-open No. 2002-254664 (Pages 2, 4, and 6, and FIG. 3 and FIG. 13), and Japanese Patent Application Laid-open No. H9-187954 disclose that a process called a suction purge are performed periodically in order to prevent these defects. In the process of suction purge, the nozzle group in the nozzle surface is covered by a suction cap which is connected to a negative pressure generating mechanism such as a suction pump, and a negative pressure is generated inside the suction cap by the negative pressure generating mechanism, and impurities in the nozzle are discharged by sucking the ink from each nozzle group. Moreover, the nozzle group of the recording head is covered by a preserving cap, and the nozzle group is preserved for preventing drying of ink and adhering of impurities in the nozzle when not in use. At the same time, the ink is kept moist by the preserving cap.
An outer peripheral lip portion which makes a contact with the nozzle surface to surround an area around the nozzle group is provided to a preserving cap. the outer peripheral lip portion is brought into contact with the nozzle surface, in a state of applying a predetermined load (capping load) to the suction cap and the preserving cap for ensuring an airtightness when covered.